Many individuals in today's society maintain profiles in one or more social networking systems (SNS) such as Facebook, LinkedIn, or Foursquare, Flickr, Twitter and the like. Such an SNS allow its users to establish and maintain personal friend or professional relationships with other users of the same SNS. Many SNS′ also allow users to divide their friends into friend groups, e.g., best friends, work colleagues, family, etc., so as to restrict access to certain profile data to members of a particular group or subgroup. The establishment and maintenance of an SNS profile, including friend relationships and groups, is a continuous and very time-consuming process, which also entails a lock-in effect that becomes stronger the more friends a user maintains. At the same time, numerous competing SNS′ do exist and typically not all relationships can be managed within a single SNS. Therefore, users of an SNS can be forced to maintain relationships in different SNS′.
However, a privacy preserving re-use of relationships within one SNS in another SNS is not possible. Moreover, a major problem in this context is that users cannot utilize the friend relationships and groups that are defined in an SNS for access control outside of this SNS, such as in another computer system like a multiuser computing system or in other SNS′.
For example, consider a user Alice who has, e.g., a Facebook or Flickr profile with numerous carefully selected friends as well as several well-maintained friend groups. When Alice joins another SNS such as, e.g., Foursquare—where users can, e.g., indicate their physical presence at venues such as bars, restaurants or shops via a check-in—Alice might want only her Facebook friends, or the members of one of her Facebook friend groups, to access her (privacy-sensitive) Foursquare check-ins. However, current SNS do not allow for such kind of access control; they only allow for access control rules that are based on SNS-internal profile data, that is, SNS profile data that resides within each SNS whose profile data access is controlled. In the above example, a conventional and technically feasible solution for this access control problem would be to allow, e.g., Foursquare to query Alice's Facebook friends: given a user Bob who has a profile on Facebook and Foursquare, on Bob's login to Foursquare, Foursquare retrieves Alice's current Facebook friend list and determines whether Bob is a Facebook friend of Alice. A drawback of such a conventional solution, however, is that Foursquare learns all Facebook friends of Alice, which compromises Alice's privacy.
Additionally, to enable such a solution in the first place, it is necessary that both Alice and Bob make their Facebook identities (e.g., their Facebook usernames) known to Foursquare so that Foursquare and its provider (a) knows whose Facebook user's friends to query, and (b) can recognize Bob in Alice's friends list. This identity disclosure is another drawback of the conventional solution.
Related technology is, e.g., disclosed in WO 2011/140 263 A1. In this document, the following has been disclosed: methods and systems for providing access to information and connections associated with or derived from social graphs, including social networks, professional networks, and content sharing and public sights.
In WO 2012/089 007 A1, a system for providing shared content to a group of users in a multi-platform environment is disclosed. The system allows making digital content items available across platforms.
Hence, there is a need to more intelligent access resources on a computer system without having to use a dedicated access control system, e.g., on the computer system.